At present, the companies supplying the digital hearing aid normally focus their attention on increasing the power of the hearing aid for obtain more higher audio outputting signal, or by suing the way of suppressing the environment noise or eliminating echoing sound signal, etc, to ensure the quality of the outputting signal. The consequence is that: even the quality of the outputting signal is very good, however the gain portion in the user actually received signal is quite less so that the user still cannot obtain a good listening effect. Normally, a customized hearing aid is put on the auricle of the user, a behind-the-ear aid is put behind of the ear of the user, and there is a distance between the sound from the speaker and the eardrum of the user. The interaction between the resistance of the sound transmission and sound deflection made sound loss when the sound is transmitted in the ear canal with complicated physiological structure. In general, there is about 20%˜30% gain loss so that many severe hearing loose patient complaining the power of the hearing aid being not enough.
For enhancing the wording efficiency and improving the invisibility of wearing, completely-in-the-canal (CIC) hearing aid or in-the-ear hearing aid is created, so that reduced the loss which happened during the transmission in ear. Thanks to the volume of the in-the-ear hearing aid is very small, the room for arranging the parts is very limited, so must design and make the parts as small as possible, meantime the assembly should be quite impact. The disadvantage caused by smaller size is power of the hearing aid has to reduce accordingly; the sound gain effect is expected cannot be great.
Completely-in-the-canal (CIC) hearing aid is a kind of hearing aid customized, need to take ear-impression for each hearing-impaired patient in fitting centre in advance, then sending the ear-impression to the plant and manually make as the housing of the hearing aid. Thanks to the main body of the hearing aid does not exposed outside of ear, its invisibility being very high is a object which is pursued by part of hearing-impaired patients, however, rather because it being put inside of the ear, the adverse effect could be produced would be occlusion effect, echo howround, effecting to the wearing stability which resulted from the hard contacting with the whole ear canal and not adapting the movement of the muscle of ear canal, and the difficulty of cannot be put in depth ear canal which resulted from the complicated 3-dimensioned physiology-anatomy structure, etc.
For letting the fitting centre can obtain the common acknowledge when they are filling the “customized hearing aid customer order”, give convenient to the fitting centre when they select the ear canal length of the customized hearing aid, improving the success rate of their first time fitting, especially, the literal report gives standard definition to the 3-dimensioned physiology-anatomy structure. Hereby, by taking reference to FIG. 12, explaining short ear canal 21, middle length ear canal 22, long ear canal 23, deep ear canal 24, etc.
Short ear canal 21: Not exceed the central line of the first curved conduit and the second curved conduit (generally, suit for the hearing aid fitting patient whose hearing impairing rather small, not suit to CIC patient)
Middle length ear canal 22: exceed the central line of the first curved conduit and the second curved conduit, not exceed the second curved conduit (suit for the hearing aid fitting patient whose hearing impairing not very severe, but not suit to CIC patient)
Long ear canal 23: exceed the second curved conduit about 1 mm (suit for the hearing aid fitting patient whose hearing impairing is somehow severe, or suit to CIC patient)
Deep ear canal 24: exceed the second curved conduit 3˜5 mm (suit for the hearing aid fitting patient whose hearing impairing very severe and reach the limitation of hearing aid fitting, not suit to the situation of the curvature of the second curved conduit of the patient is very large, the situation of loss of hearing is quite good, or the old aged ITE selecting patient)
Universal in-the-ear hearing aid is the new completely-in-the-canal (CIC) hearing aid which developed in the recent years on the base of common customization, there is no need for each patient take the ear-impression and special manual manufacture for such a hearing aid. However, its positioning in the ear canal mainly depends on the earplug with greater protrusion end, hard plastic main body hardly contact with the ear canal and slides along with movement of the muscle of ear canal caused by the activity like talking, eating, drinking etc. The main problem is that it is hardly extending into the depth of ear canal, can not eliminate the occlusion effect and echo howround, the wearing stability and extent of comfort is rather bad.
U.S. utility patent numbered by U.S. Pat. No. 7,092,543B1 discloses a common in-the-ear hearing aid, as shown in FIG. 13, the speaker portion of this in-the-ear hearing aid is able rotate flexibly, belongs the in-the-ear hearing aid which suit for use in anybody's ear canal, its speaker extending into the inside of ear, comparatively closer to human eardrum located in depth of ear canal, reduced the gain loss which caused during the sound transmission in the ear canal, improved the work efficiency of the hearing aid. A fixed pulling line or pole disposed at the rear end of the in-the-ear hearing aid, made the taking out of it is very convenient. However, the angle of elevation of the speaker portion is not larger than 30 degree, can not adapt to the requirement of turning angle of the human ear canal is up to 60 degree; There is no air circulation near the central part of ear canal during use and sweating situation exist, so as to make the user feels not comfortable, also it is hardly to be put to where is close r to human eardrum.
FIG. 14 is a structure illustrative view of a universal in-the-ear hearing aid supplied by UNITRON, its stent maintain a space from the ear canal, ensured the air circulation in ear, there is no sweating although long time wearing, and the speaker is closer to human eardrum, reduced the gain loss which caused during the sound transmission in the ear, improved the work efficiency of the hearing aid. A pulling pole disposed at the rear portion of this in-the-ear hearing aid, so as to convenient the taking out of the hearing aid. However, its sound transmission device is a rigid connection, in such, the hearing aid will often meets the following situation during use: The outer housing of in-the-ear hearing aid is a rigid housing with unchangeable shape, when it is put in the ear of human, resulting from difference in the length and shape of the ear canal, a non-even contacting exist between the outer housing and the ear canal, some portion of ear canal exerted very high pressure, made the user feel uncomfortable. Its positioning mainly depends on the earplug with protruded end, the hard plastic made main body hardly contact with the ear canal and slides along with the movement of the muscle of ear canal. The main problem is that it cannot bend, cannot extended into the ear canal with complicated 3-dimensioned structure, cannot eliminate the occlusion effect and echo howround, the stability of wearing and extent of comfortable is very bad.